Pokemon Co. has released a statement in Japan about a rather unforutnate situation. It seems that a number of different fake Pokemon Center Online websites have popped up, and they're nothing more than phishing scams to steal credit card info. You can see Pokemon Co.'s (Google translated) statement on the matter below.
Recently, it has been confirmed that personal information is stolen and the credit card is illegally used on a fake website masquerading as "Pokemon Center Online", the official online shopping site for Pokemon goods. In order to prevent damage, please be careful not to access any websites that you think are suspicious and do not enter or disclose personal information such as credit card information. In addition, please contact the nearest police station if you are affected by such a site.